To a large degree, since the beginning of time, charisma or the lack of it has impacted upon those in quest of acclaim. As media expands, this has become ever more vital. Thus, demeanor if unappealing, can defeat one's likelihood of success, causing the death of prospects whilst they are still embryonic.
For I must not measure the speech of a statesman to his people by the impression which it leaves in a university professor, but by the effect it exerts on the people. And this alone gives the standard for the speaker's genius.